A woman prayed Maghrib salah, and then immediately afterwards began performing the two rak'ah sunnah salah. During the sunnat prayer, she felt that she has had white discharge. After finishing the sunnah, she checked her clothing and confirmed that there was indeed a discharge.
Does she also have to repeat her fard salah, despite her having no knowledge of any discharge at the time of performing it, or does she only have to repeat just that salat during which she intially felt the discharge?
There is a rule of jurisprudence which applies is such situations. "Certainty cannot be obliterated by doubt".
In this case, the fact that she performed Wudhu makes it certain that she is in the state of purity. Therefore, this certainty cannot be nullified by the mere doubt that the discharge could have been there while she was performing her Fardh. Especially seeing that she only felt it after her Fardh was completed. Hence, she will only have to repeat the Salaah during which she initially felt the discharge.
The ruling for a woman who discharges frequently (to such an extent that it goes unnoticed at times) is:-
(1) Her Salaah will be valid as long as she is not certain that discharge came out in Salaah. (Mere doubt of discharge flowing during Salaat will not render her Salaah invalid.)
(2) Such a woman should insert a tampon, pad etc. This will help to absorb the discharge. Until the discharge does not show on the area of the pad which is beyond the inner part of the vagina, Wudhu will not break. (Ahsan-ul-Fatawaa, Page 80, Part 1)